Table 1.

Electroencephalographic Background Categories

Category	Background Patterns
A	Suppressed background (<10μV) without discharges Suppressed background (<10μV) with continuous periodic discharges Burst‐suppression background (with or without discharges) with suppression (<10μV) or attenuation (>10μV, but <50% of background voltage) periods constituting >50% of the recording
B	Abundant periodic discharges (>50% of recording). Abundant rhythmic SW (polyspike/spike/sharp and wave; >50% of recording) Unequivocal electrographic seizure (at least 1) Discontinuous background with suppression periods (<10μV) constituting >10% of the recording Low‐voltage background (most activity is <20 μV)
C	Absence of all features stated above